The term “tree hugger” evokes a simpler time, one long before there was a consensus that climate change posed an existential threat to humanity, when caring about the environment largely seemed to be the preserve of a small group of activists. In popular culture, tree huggers are usually well-meaning, a little eccentric and easily dismissed as hippies. 

But public imagination is fickle; history is much more violent. The original tree huggers were the people of Khejarli, a village in modern-day Rajasthan in India. In 1730, the Maharaja Abhai Singh gave an order to cut down trees in the village for the construction of a new palace. The villagers, for whom the trees were sacred, hugged them to prevent the soldiers from felling them. It was a massacre. After 363 people were killed, Abha...